The invention relates to analog amplifiers. Since the introduction of transistors and integrated circuits, analog amplifiers have been used in many applications Example applications range from video processing, audio processing, radio-frequency circuits, networking and sensor related fields. Amplifiers are often the fundamental building block of many analog systems. These systems include signal amplification, digital-to-analog converter, analog-to-digital converter, output drivers and sensor interfacing circuits, and they require amplifiers.
In these systems or applications, the overall performance is highly dependent on the performance capability of the individual amplifiers. Often, the system performance is limited by the amplifiers. Therefore, it is important to maximize the amplifier performance, and one of the critical performance factors is the gain.
Various amplifier designs have been developed in an attempt to meet high performance requirements. These include folded-cascode amplifiers, which are known in the art, and need not be described here. The closest prior art is thought to be represented by U.S. Pat. No. 6,362,688, and U.S. Pat. No. 6,828,856, both disclose prior gain boosting circuitry. Yet, such designs have not been addressing the increasing demand for high performance with flexible operating supply voltages and biasing conditions. Thus there is a need for a gain-boosting amplifier that requires simple configuration and offers wide range of supply voltage and biasing condition. The present invention addresses such a need.